1. Field of the Invention
The present invention relates to an interchangeable lens detachably attached to a camera body which includes a motor (body-motor) for driving at least one movable lens group of the interchangeable lens and a power source for the body-motor.
2. Description of the Related Art
In interchangeable lenses for cameras, that are detachably attached to a camera body, it is ideal that one or more movable lens groups (e.g., focusing lens group) be driven by a motor (lens-motor) provided in the interchangeable lens, not by a motor (body-motor) provided in a camera body to which the interchangeable lens is mounted. This is because the lens-motor is adopted according to specifications of the photographic optical system provided in the interchangeable lens itself, whereas the body-motor is adopted irrespectively of specifications of the photographic optical system provided in the interchangeable lens. An interchangeable lens having a lens-motor provided therein is disclosed in, e.g., Japanese Patent Publication No. 2503997.
However, such an interchangeable lens having a lens-motor provided therein has the following problem.
Namely, in the case where the camera body to which the interchangeable lens is to be mounted is of a type incorporating a body-motor, the lens-motor cannot be actuated even when the interchangeable lens with the lens-motor is mounted to the camera body because the power source in the camera body cannot supply power to the lens-motor. On the other hand, the interchangeable lens having a lens-motor is provided with no power transmission device for transmitting power of the body-motor of the camera body to the interchangeable lens mounted thereto. Therefore, it is conventionally the case that the interchangeable lens having a lens-motor can be applied solely to camera bodies designed to be capable of supplying power to the lens-motor of the interchangeable lens, and therefore, cannot be used for other types of camera bodies which can use an AF function.